Shutter Speed, ISO, and Aperture

If you are a beginner in photography, you MUST know it.

Exposure refers to the amount of light that enters the camera and hits its digital sensor.It is basically the measure of how dark or bright a photograph is.

If the image is too bright, it is then said to be overexposed.This is whereby too much light has been allowed to hit the camera’s sensor.If it’s too dark, it is said to be underexposed and not enough light has been allowed to hit its sensor.

e.g

{above is an example of an underexposed image}

{above is an example of an overexposed photograph.}

APERTURE

The aperture refers to the size of the opening in the lens through which the light enters the camera. The size of this opening can be adjusted and the aperture size is measured in f-stops. The image on the right shows you exactly what the aperture on a lens looks like.

When you change the f-stop value, you change the size of the opening. Here’s the weird thing though. The higher the f-stop, the smaller the opening.

Take a look at the chart below to see what different apertures look like at different f-stops. On the far left, you can see that setting an aperture of f16 will result in a small opening. Choosing an aperture of f1.4 will result in a very wide opening.

The choice of aperture affects your photograph, but the most noticeable affect your choice of aperture and on the depth of field.

SHUTTER SPEED

The shutter speed refers to the length of time the opening in the lens remains open to let light into the camera and onto the sensor. The shutter speed can be as fast as 1/10,000 of a second or as slow as several minutes.Fast shutter speeds have the effect of freezing motion in the scene you are photographing. Conversely, slow shutter speeds will blur motion in a scene. Both of these can be used to great creative effect.

The chart below shows how different shutter speeds would effect the sense of motion if you were photographing a person running. Fast shutter speeds will freeze the motion. This technique is often used in sports photography. The slower the shutter speed becomes, the more blurred the person running becomes in the photograph.

ISO

The ISO refers to how sensitive the digital sensor in your camera is to light. The lower the ISO number, the less sensitive it is to light. Setting a higher ISO number increases the sensitivity of your camera sensor to light. Most cameras have ISOs ranging from about 50 or 100 ISO right up to 16,000 ISO or higher.

As you increase the ISO value, your camera sensor becomes more sensitive to light. This means that you can achieve higher shutter speeds. This can be extremely useful when shooting in low light without a tripod. You may find that shooting at 100 ISO results in shutter speeds that are too slow to hand hold without camera shake. By increasing the ISO to 800 ISO, for example, you may find that your shutter speed is now fast enough to hand hold.